Is her aim possibly to go to a space station? (6)
I believe the answer is:
'is her' is the definition.
'aim possibly to go to a space station?' is the wordplay.
'possibly' is an anagram indicator.
'to go to' is a charade indicator (letters next to each other).
'a space station?' becomes 'Mir' (I've seen this in another clue).
'aim' anagrammed gives 'iam'.
'iam' put after 'mir' is 'MIRIAM'.
(Other definitions for miriam that I've seen before include "Biblical girl's name" , "Biblical sister of Moses" , "Things classed together" , "Sister of Moses and Aaron" , "-- Makeba, South African singer" .)